Great ingredients make for great meals. Whenever you can, use the highest quality supplies for your recipes. The flavor difference will always come through in your finished dish.
If there is an ingredient that you are not familiar with, check our Ingredient section. There are pages and pages of information about the ingredients used in my recipes.
As I've mentioned elsewhere, baking is essentially like working with a chemistry set. Exact measurements are important because of how a little more leavening agent or moisture can affect the finished product. The problem is that all of this can also be affected by the ingredients themselves.
For instance, the moisture content in flours varies greatly. Not only is this different between different manufacturers of flours, but flour loses moisture during storage.
As you knead or mix flour, it will pick up moisture. If it is a humid day you may actually need slightly more flour. Or, if your flour has been stored a long time, you may need less because of the lower moisture content. This is why baking is an art (um, chemistry).